The present invention relates to a catalyst component for polymerization or co-polymerization of xcex1-olefin, or more particularly to a solid complex catalyst of superior catalytic activity and stereoregularity, which is supported in a carrier containing magnesium.
So far, quite a few catalysts and polymerization processes relative to homo-polymerization or co-polymerization of olefin have been reported, but the development of new catalysts is further demanded both for the improvement of polymer properties and for the production of polymers of specific desired properties.
Magnesium-containing catalysts for polymerization of olefin are known to have high catalytic activity and accord good stereoregularity, and are also known to be suitable in gas phase polymerization. In catalysts used in gas phase polymerization, the shapes, sizes and distribution of the particles as well as their catalytic activity and the polymers"" stereoregularity, are matters of importance in the interest of industrial operations. Especially it is important that catalysts of narrow particle size distribution be produced. Catalysts of broad particle size distributions need be avoided since catalysts of small particle sizes are apt to cause trouble in transit, and those of very large particle sizes may result in polymers like lumps or reels of strings while polymerizing. For instance, in order to produce impact-resistance copolymers of ethylene and propylene having high contents of ethylene, with the polymer""s average particle size as large as 1,000 xcexcm or so, the average particle size of the catalyst for co-polymerization should be in the range of 30 to 80 xcexcm. The catalyst must also be of excellent mechanical strength against erosion during the polymerization process, and must be excellent enough in bulk density, too. Thus, in development of polymerization catalysts, a simple production process and yet of adjusted particle sizes of the catalysts can be important more than anything else.
The catalytic activity and the stereoregularity of polymerized xcex1-olefin are very important fundamental property for a catalyst and therefore many researches of improving them have so far been performed. As a consequence, there is no longer a need in most industrial production of polyolefin, especially polypropylene, today for a separate process for removal of the residue and atactic component of the catalyst. However, as uses of polypropylene of better properties, especially the greater strength, are on the rise nowadays, development of catalysts of greater stereoregularity is acutely demanded to meet the ever-growing need for such.
Many magnesium-containing titanium-based catalysts for polymerization of olefin along with the production processes for such catalysts have been reported. Especially, quite a few processes making advantageous use of magnesium solutions for obtainment of olefin polymerization catalysts with adjusted particle size, as above, have been reported. Methods for obtainment of magnesium solutions by reacting magnesium compounds with such electron donors as alcohol, amine, cyclic ether, carboxylic acid in the presence of hydrocarbon solvents are known, of which, the cases wherein alcohol was used are mentioned in U.S. Pat. Nos. 4,330,649; 5,106,870. Now U.S. Pat. Nos. 4,315,874; 4,399,054; 4,071,674; 4.439,540, too, have reported methods for production of magnesium solutions. Tetrahydrofuran, which is cyclic ether, has been in various uses as a complex compound of magnesium chloride (e.g. U.S. Pat. Nos. 4,277,372; 3,642,746; 3,647,772), as additive to co catalyst (U.S. Pat. Nos. 4,158,642; 4,148,756), and as a solvent (U.S. Pat. No. 4,477,639; 4,518,706).
U.S. Pat. Nos. 4,946,816; 4,866,022; 4,988,656; 5,013,702, and 5,124,297 are all mutually interrelated, and the processes for production of catalysts revealed in these patents comprise: (i) producing a magnesium-containing solution from magnesium carboxylate or magnesium alkylcarbonate; (ii) precipitating said magnesium solution in the presence of a transition metal halide and organosilane additive, (iii) re-precipitating the precipitated solid component with the use of a liquid mixture containing tetrahydrofuran, and (iv) reacting said reprecipitated particles with transition metal component and an electron donor compound. But such methods as these are not free from inherent demerits of having to undergo too many steps in production of catalysts.
U.S. Pat. No. 4,330,649 describe that a magnesium solution is made by reacting a magnesium compound with alcohol, organic carboxylic acid, aldehyde, amine or their mixture in the presence of an organic hydrocarbon solvent, and the final catalytic substance is made by reacting the above solution with a titanium compound and an electron donor.
Meanwhile, U.S. Pat. Nos. 4,347,158; 4,422,957; 4,425,257; 4,618,661; 4,680,381, commend a method for production of catalysts by grinding magnesium chloride, after adding thereto a Lewis acid compound like aluminum chloride. Although there have been some improvements on the catalytic activity, there yet remain some morphological irregularities in the shape, and broad size distribution, and also the stereoregularity needs to be improved.
As has been reviewed above, keen need is still felt for development of catalysts for olefin polymerization, which are simple in production process, high polymerization activity, large average particle size, narrow particle distribution, suitable in gaseous phase polymerization, and give the excellent stereoregularity of polymer obtained.
Disclosed herein is a solid catalyst for polymerization or co-polymerization of olefin, which shows high catalytic activity, large average particle size, narrow particle distribution, and improved stereoregularity.
Also disclosed is a simple process for production of a solid catalyst for polymerization or co-polymerization of olefin, which has high catalytic activity, excellent stereoregularity, large average particle size, and narrow particle distribution.